The invention relates generally to public-key cryptography and key distribution.
Key distribution is a common problem with public-key cryptography. Many times, and increasingly often in electronic commerce, a user may wish to communicate with another user (or merchant, as the case may be), without first having his key. For example, in electronic commerce, the situation may arise where a consumer wants to purchase something from a merchant but does not have the merchant's public key or the public key of the merchant's bank. We may assume, however, that the consumer does have the merchant's name and/or the merchant's E-mail address Since the consumer has the merchant's email address, she can easily get the information to the merchant, but without the merchant's public key cannot encrypt the GSO for the merchant or, more importantly, the PI for the merchant's bank.
To bootstrap communications, a Diffie-Hellman protocol could be used, or a directory service might be consulted. Both of these methods have the same drawbacks for the user (consumer): they require multiple passes and services must be immediately available in order for communication to occur.
A scheme is described below which solves the problem in a single pass.